Ending nuclear weapons before they end us: current challenges and paths to avoiding a public health catastrophe.

The United Nations Treaty on the Prohibition of Nuclear Weapons (TPNW)-an important planetary health good-entered into legal force in January 2021. Evidence of the consequences of nuclear war, particularly the global climatic and nutritional effects of the abrupt ice age conditions from even a relatively small regional nuclear war, indicates that these are more severe than previously thought. None of the nine nuclear-armed states is disarming; instead, all invest enormously in new and more hazardous nuclear weapons. Nor has any of the 32 states claiming reliance on another state's nuclear weapons yet ended such reliance. These factors, abrogation of existing nuclear arms control agreements, policies of first nuclear use and war fighting, growing armed conflicts worldwide, and increasing use of information and cyberwarfare, exacerbate dangers of nuclear war. Evidence-based advocacy by health professionals on the planetary health imperative to eliminate nuclear weapons has never been more urgent.